One of the greens I bought yesterday. Since I wasn't familiar with its taste, I decided to do it fairly plain and on its own. I also browsed through my cookbooks for the basics of how to handle it. Here are the results.

Basic handling of choi sum: Wash in running water and shake off excess water; separate leaves from stalks; separate stalks from each other. Blanch stalks in boiling water or stock.

At this point, it can be treated like any other greens. Apparently, the traditional Chinese thing to do is to serve the blanched stalks on their own with oyster sauce.

What I did was make a basic stir-fry with it and eat it with noodles. So, I made my basic stir-fry base (heat oil, add salt, garlic, ginger and chopped chilli), then stir-fried the choi sum (leaves and blanched stalks together), and finally added soy sauce and the cooked noodles. Drizzled some sesame oil on top and ate. Very nice. The flavour of the choi sum is mild but distinctive, and not like cabbage at all (also sweeter).